Inerting and venting system

Abstract

An inerting and venting system for an aircraft. The inerting and venting system includes a tank containing fluid to be inerted, a mixer including an operating flow path and a mixing flow path, a vent line fluidly connecting ambient atmosphere to the operating flow path of the mixer, and an inert gas line fluidly connecting an inert gas source to the mixing flow path of the mixer. The mixing flow path and the operating flow path are arranged in a coflowing configuration such that ambient air communicated by the operating flow path mixes in a coflowing manner with inert gas communicated by the mixing flow path and the coflowed mixture is directed into the tank. The inerting and venting system may include a first valve for controlling flow of vent air from ambient atmosphere to the tank, and a second valve for controlling flow of inert gas from an inert gas source to the tank. A valve adjuster is configured to passively adjust the first and second valves in response to a pressure differential between the ambient atmosphere and the tank, and to control ratio of flow in response to oxygen concentration in the inert gas or the tank ullage gas.

What is claimed is: 
     
       1. An inerting and venting system for an aircraft, comprising:
 a tank containing fluid to be inerted; 
 a mixer including an operating flow path and a mixing flow path; 
 a vent line fluidly connecting ambient atmosphere to the operating flow path of the mixer; and 
 an inert gas line fluidly connecting an inert gas source to the mixing flow path of the mixer; 
 wherein the mixing flow path and the operating flow path are arranged in a coflowing configuration such that ambient air communicated by the operating flow path mixes in a coflowing manner with inert gas communicated by the mixing flow path and the coflowed mixture is directed into the tank, 
 wherein the operating flow path has a vent pipe section that includes a converging section; 
 a vent air valve configured to control flow of vent air from the ambient atmosphere to the operating flow path; and 
 an inert gas valve configured to control flow of inert gas from the inert gas source to the mixing flow path. 
 
     
     
       2. The inerting and venting system of  claim 1 , wherein the mixer is connected at an interface of the tank and the vent line such that the resulting coflowed mixture is directly discharged into the tank. 
     
     
       3. The inerting and venting system of  claim 1 , wherein the mixing flow path includes one or more nozzles that inject the inert gas into the ambient air communicated by the operating flow path. 
     
     
       4. The inerting and venting system of  claim 1 , wherein the mixing flow path includes one or more nozzles and wherein the ambient air communicated by the operating flow path entrains the inert gas from the one or more nozzles, or vice versa, and the entrained mixture is directed into the tank. 
     
     
       5. The inerting and venting system of  claim 1 , wherein the mixing flow path has a flow axis that is disposed coaxially relative to a flow axis of the operating flow path. 
     
     
       6. The inerting and venting system of  claim 1 , wherein the mixing flow path has a flow axis that is disposed at an oblique angle relative to a flow axis of the operating flow path. 
     
     
       7. The inerting and venting system of  claim 1 , wherein the inert gas line is a high flow line, and further including a low flow inert gas line between the inert gas source and the tank. 
     
     
       8. The inerting and venting system of  claim 1 , wherein the tank includes a plurality of fuel compartments, and further including a mixer associated with each fuel compartment, wherein the mixer associated with each respective fuel compartment is located so as to control the flow of inert gas from the inert gas line into the fuel compartment. 
     
     
       9. The inerting and venting system as in  claim 8 , wherein a portion of the vent line and inert gas line in at least one fuel compartment is integrated into a wall of the fuel compartment, and mixers are distributed along the tank wall surface in the respective fuel compartments to provide distributed control of ambient air and inert gas into the fuel compartments. 
     
     
       10. The inerting and venting system as in  claim 1 , wherein the inerting and venting system is a closed loop, passive, localized control system. 
     
     
       11. The inerting and venting system as in  claim 1 , comprising a valve adjuster mechanically coupled to the vent air valve and the inert gas valve to adjust the vent air valve and the inert gas valve. 
     
     
       12. The inerting and venting system as in  claim 11 , wherein the valve adjuster is integrated in the mixer. 
     
     
       13. The inerting and venting system as in  claim 11 , wherein the valve adjuster is configured to adjust the vent air valve and the inert gas valve simultaneously. 
     
     
       14. The inerting and venting system as in  claim 11 , wherein the valve adjuster is configured to adjust the inert gas valve proportionally relative to the vent air valve. 
     
     
       15. The inerting and venting system as in  claim 11 , wherein the valve adjuster includes a proportional control actuator configured to adjust the inert gas valve and the vent air valve in response to increases and decreases in atmospheric pressure relative to tank pressure. 
     
     
       16. The inerting and venting system as in  claim 15 , wherein the proportional control actuator is configured to cause the inert gas valve to allow a greater amount of inert gas flow than the amount of vent air flow allowed by the vent air valve as atmospheric pressure increases relative to tank pressure. 
     
     
       17. The inerting and venting system as in  claim 15 , wherein the proportional control actuator is configured to cause the inert gas valve to allow a lesser amount of inert gas flow than the amount of vent air flow allowed by the vent air valve as atmospheric pressure decreases relative to tank pressure. 
     
     
       18. The inerting and venting system as in  claim 15 , wherein the proportional control actuator includes a stimuli sensitive material. 
     
     
       19. The inerting and venting system as in  claim 11 , comprising a pressure differential actuator configured to open or further open the inert gas valve and the vent air valve in response to atmospheric pressure increasing relative to tank pressure. 
     
     
       20. The inerting and venting system as in  claim 11 , comprising a pressure differential actuator configured cause the inert gas valve and the vent air valve to close or approach a closed position in response to atmospheric pressure decreasing relative to tank pressure.